`dolt login` works with DoltHub, but not a DoltLab instance

[coffeegoddd]

dolt login command works with www.dolthub.com, but in not configurable to work with a deployed DoltLab instance

[timsehn]

This works now:

dolt login --insecure --auth-endpoint 35.161.18.21:50051 --login-url http://35.161.18.21/settings/credentials